The development team come with this intro:
TIO is a family of online interpreters for an evergrowing list of practical and recreational programming languages.
To use TIO, simply click the arrow below, pick a programming language, and start typing. Once you click the run button, your code is sent to a TIO arena, executed in a sandboxed environment, and the results are sent back to your browser. You can share your code by generating a client-side permalink that encodes code and input directly in the URL.
You can test a total of 500 programming languages.
You can test it at official webpage.
This is a screenshot with all programming languages: